(a) Field
The subject matter disclosed generally relates to hole openers. In particular, the subject matter relates to drill-bits.
(b) Related Prior Art
Hole openers have long been used in the HDD (Horizontal Directional Drilling) industry as well as in any geological well drilling applications. Traditional hole openers consist of roller cones (built in varying configurations) designed to pound, cut and penetrate rock formations. These “roller-cone” rock bits have been in use since the first design was patented by Baker Hughes in 1909. Since then, the roller cone rock bit has evolved through numerous iterations. The concept, in its most basic of terms, consists of one or more metal toothed, cone shaped, bearing driven cutters that literally roll over the rock continuously while the drilling rig applies pressure or weight from above. As these cone cutters roll over the rock, the metal teeth pound, cut and chew up the rock, allowing the bit to slowly penetrate the formation. An example of a traditional roller-cone rock bit is shown in FIG. 1A.
Another example of a traditional hole opener is shown in FIGS. 1B and 1C. These hole openers are typically referred to as split bits or cone cutter reamers. Generally these hole openers define a rotation shaft around which there is provided two or more drilling cones.
Although such hole-openers/reamers have achieved considerable popularity and commercial success in the HDD application, they frequently experience failures and cause increasing job costs (which are a significant burden to drilling companies). For example, it is a common occurrence for drillers to lose cones from their split bit reamers. This happens for a variety of reasons. Whether it is poor construction of the tool, overuse, or other extenuating circumstances. Cone loss is a constant and looming threat. Having this happen on a bore can be catastrophic. This causes the need for the drilling Company to either fish out the lost cone, and in some cases start the bore again from scratch. All of this is done at the cost of the drilling company.
There is therefore a continuous need for an improved drilling bit which is durable and at the same time achieves a higher drilling speed and less failure.